Effect of sensory education on school children’s food perception: A 2-yearfollow-up study

Effect of sensory education on school children’s food perception: A 2-yearfollow-up study

Effect of sensory education on school children’s food perception: A 2-year

follow-up study

Department of Food Technology, University of Helsinki, P.O Box 66, FI-00014 University of Helsinki, Finland

a r t i c l e i n f o

Article history:

Received 19 October 2007

Received in revised form 4 October 2008

Accepted 4 October 2008

Available online 11 October 2008

Keywords:

Child

Sensory education

Taste

Smell

Food perception

Neophobia

a b s t r a c t

We studied the effect of sensory education on taste and odor awareness and food ratings in school children Second and fifth graders (n = 244, 7–11 years at the baseline) from two schools in Helsinki area participated

in the study At the completion of the study at two years, the groups consisted of 96 (education, school one) and 79 (control, school two) students At baseline and in four follow-up measurements, both groups per-formed six tasks: (1) free odor naming (five odors), (2) taste identification (six solutions), (3) descriptive characterization of two breads, (4) ratings of the extent to which subjects paid attention to sensory prop-erties of food, (5) willingness-to-try ratings of unfamiliar vs familiar foods and (6) aided odor naming (five odors, 10 verbal labels) Subsequently, the education group received two waves of sensory education: the first wave comprised of 10 Classes du gỏt lessons and the 2nd of 5 lessons familiarizing the children with different food categories The second wave was performed only for 2/3 of the education group The edu-cated children improved their skills in identifying tastes and odors, and characterizing foods, while no dif-ference was seen in the performance of the control group However, effects of education were mainly observed for the younger children only Although the improvements were small and not always consistent over the study period, their general direction was encouraging: the sensory education activated children’s odor and taste perceptions and improved their ability to describe sensory properties of food

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1 Introduction

Flavor preferences established early in life track into later

children’s use of their senses of taste and smell, and learning their

preferences, is still rather scarce It is, however, well known that

found that children under five years base their food preferences

on two dimensions: sweetness and familiarity Thus, children’s food

preferences and dietary choices might be driven primarily by

sen-sory qualities of food, whereas adults tend to be more concerned

A common belief is that children are more sensitive to smell and

taste stimuli than adults, although researchers have not been able

may be a misconception due to children’s tendency not to accept

new or unfamiliar foods, called neophobia Neophobia is a

protec-tive mechanism preventing animals and humans from eating what

could be harmful to them At the same time it leads humans to

choose the familiar and safe food instead of new and unfamiliar,

potentially harmful food Neophobia appears in all age groups,

exposures to a large variety of unfamiliar foods can reduce the

can reduce their food neophobia Thus, humans tend to widen their preferences also to initially rejected foods, but they need a

espe-cially in children The present paper describes a sensory education program that provides children social interaction with their peers

as well as increases their awareness of and curiosity towards foods Sensory education may act as the compelling force needed to increase willingness to taste unfamiliar foods

In industrialized countries, changing society and busy lifestyles drive people to more convenient and, at the same time, to

barrier to planning regular and balanced meals in the family: par-ents are busy and the need for convenience drives them more and more often to feed their children with easy options like fast food or

0950-3293/$ - see front matter Ĩ 2008 Elsevier Ltd All rights reserved.

* Corresponding author Present address: Valio Ltd, R&D, P.O Box 30, FI-00039

Valio, Finland Tel.: +358 10 381 3047; fax: +358 10 381 3372.

E-mail address: sari.mustonen@valio.fi (S Mustonen).

Food Quality and Preference

j o u r n a l h o m e p a g e : w w w e l s e v i e r c o m / l o c a t e / f o o d q u a l

Kokkonen, 2003) This kind of a change does not promote the

chil-dren and adolescents to repeatedly choose the same and familiar

foods, causing monotonous and unhealthy diet in the long run

future generation may be unable to demand high quality or to have

the courage to try new, exotic foods Therefore, it is important to

invent and develop new ways to encourage children to try different

foods and pay attention to the quality of foods This may eventually

have beneficial effects on children’s diets in terms of greater

vari-ety and better quality of food

‘‘taste lessons” (Classes du gỏt) This education program for school

children has been used in several European countries, e.g in

children to become well-informed consumers with awareness of

the quality and differentiation of foods through their smells,

tex-tures and tastes Children’s awareness is developed by awakening

their interest and curiosity towards foods by exercising their

senses Although widely used, the evidence of the impact of the

education program is still rather scarce To date, no systematic

re-search on the effects have been available in scientific literature

chil-dren’s interest in food quality increased and their ability to

de-scribe sensory properties of food improved compared to the

control group, but no measurements were conducted at the

base-line level Thus, development in sensory awareness over time could

children who attended the Classes du gỏt program with their

non-trained peers and adults in sensory characterization of

choco-late and found that despite the education, children described the

chocolate in their own way and adults in their own way

In Finland, we started a 2-year follow-up study with school

chil-dren, representing two age groups (7–8 and 10–11 years), to track

the development of chemosensory awareness and food-related

perceptions influenced by the program One-half of children

re-ceived up to two waves of taste lessons (first, a Finnish application

of Classes du gỏt program and second, activating lessons on main

food categories) and another half performing baseline and

follow-up measurements only Two age grofollow-ups were included to the study

to examine whether the possible effect of education would depend

on the age at which the lessons are attended The education group

was further divided into two subgroups, as the second wave of

education was given only to 2/3 of the education group, to examine

whether the children would benefit from a prolonged education

The effects of the sensory education were studied with (1) sensory

tests conducted in the laboratory and (2) background

question-naires on subjects’ food behavior that were sent to parents three

times during the follow-up period This paper describes the results

of sensory measurements at the baseline and in the four follow-up

measurements, all conducted in the laboratory during two years of

time The first education wave was expected to increase sensory

awareness, improve food description skills and increase the

will-ingness to taste unfamiliar foods Due to the nature of the lessons

in the second education wave, it was expected to maintain the

interest in chemosensory perception achieved during the first

wave, and increase the interest in trying unfamiliar foods

2 Materials and methods

2.1 Development and selection of the sensory instruments

A preliminary study was carried out during the autumn 2004 to

develop and select the sensory instruments for the proper study

Three classes of third graders and three classes of fourth graders

participated in the preliminary study, testing different sensory measurements (odor naming, taste identification, descriptive tasks, etc) The tests were conducted twice, and between the sessions one group of the children (N = 35) received a lesson on the sense of taste, another group (N = 34) received a lesson on the sense of smell and the third group (N = 40) received no lesson Children par-ticipating in the pilot taste lesson showed slight improvement in their taste identification No improvement was seen in the odor naming abilities of the group receiving the olfactory lesson, but it was expected that after a profound sensory education on tastes and odors the effects would emerge The descriptive abilities were expected to improve due to the sensory education that included descriptive tasks, although after the pilot lessons the only effect was a decrease in the number of preference-related descriptors The willingness to taste unfamiliar foods was expected to increase due to the tasting experiences and the overall increase of knowl-edge on different foods during the sensory education The tests that seemed to have potential in showing education effects in the pre-liminary study were chosen to the proper study (described in detail below)

2.2 Subjects

In the proper study, 244 students (aged 7–11 years) from two primary schools in Helsinki were recruited The schools chosen were approximately similar in size and their students had more

or less the same level of socio-economical background (between middle and high) Of the students, 175 participated in all

follow-up measurements, and are therefore included in the data analyses

In the beginning of the study, they were students at the second (7–

8 years) and fifth (10–11 years) grades in Viikki Teacher Education School at Helsinki University (education group, n = 96) and Puistola Primary School (control group, n = 79) The students from the first-mentioned school were chosen to be the education group for prac-tical reasons, as sensory lessons fitted into their curriculum The profiles of the subjects (grades and gender distribution) are shown

due to some of the students in the older group moving on to an upper level of comprehensive school, and thus to a different sys-tem or even to a new school

2.3 Overview of the proper study

At baseline (January 2005), both groups performed sensory tests, and subsequently, one group (education group) participated

in sensory education The tests were conducted four times during the two years’ period: after the first education wave (May 2005), before and after the second education wave (January and May

Additionally, a questionnaire was sent to the parents three times during the follow-up period (results reported elsewhere) The study protocol followed the ethical principles of sensory testing in our laboratory, approved by the ethical committee of

Table 1 The study population In the beginning of the study the children were 8-year-old (second graders) and 11-year-old (fifth graders).

Group and grade N boys/girls N (2005–2006) baseline

and 1st–3rd follow-ups

N (2007) 4th follow-up Education

2nd–4 th

Control 2nd–4 th

the Faculty of Agriculture and Forestry An additional approval was

applied as the subjects were minors (under 18 years of age) The

parents signed an informed consent before the study began The

subjects themselves gave a verbal assent to participate

2.4 Laboratory sessions

The measurements (lasting approximately 1.5 h) were

con-ducted in the sensory laboratory of the University of Helsinki

(ex-cept for the last session for the older group, which was performed

in the school auditoria) All measurements were made during the

school day (9 a.m to 3 p.m.) One class at a time (N = 17–28) came

to the laboratory with a teacher and performed the tasks in a given

order in ten sensory booths or at a round table with screens

pre-venting visual interaction between the ten seats During the

ses-sion, the places were switched for each task so that each subject

was placed in both the booths and at the round table In each

ses-sion, the subjects performed six tasks in the following order: (1)

pleasantness ratings, intensity ratings, and free naming of five odor

stimuli; (2) taste identification of six aqueous solutions (sweet,

salty, bitter, sour, umami, and water); (3) descriptive

characteriza-tion of two breads; (4) ratings of the extent to which subjects paid

attention to sensory properties of food; (5) willingness to taste

unfamiliar (five in the baseline and first follow-up, seven in the

second-final follow-ups) and familiar (seven) foods (the procedure

odors, list of 10 verbal labels provided) Before every task, the

sub-jects were familiarized with the evaluation forms and scales The tasks are described in detail below After the sessions, the subjects were rewarded with small food gifts (lollipops, xylitol chewing gums etc.), and in the end of the final session, they were invited

to make and consume their favorite ice cream portions using a selection of ice creams, jam, sauce, nonpareils, wafer, and decorations

2.4.1 Sensory instruments 2.4.1.1 Free odor naming and ratings for pleasantness and intensity (Task 1) The test included five aqueous aroma solutions:

(10 ml each) were presented in small brown glass vials coded with five letters (Z, D, F, X, G) and the presentation order was random-ized in five different ways for practical reasons The same five or-ders were used for each follow-up, without controlling the order individually for each child The subjects also rated the pleasantness and intensity of each sample The pleasantness was rated using se-ven categories (1 = bad and 7 = good), extreme ends supported by facial symbols, and the intensity was rated using seven categories (1 = weak, 7 = strong) The purpose of these ratings was to maxi-mize the attention paid to each sample After ratings, the subjects were asked to name each odor If uncertain, they were asked to

given to the aroma solutions at the baseline measurement 2.4.1.2 Taste identification (Task 2) The test included aqueous solu-tions of five taste stimuli (sweet, salty, sour, bitter, umami) and

presented in white plastic cups coded from 1 to 6 The presentation order was randomized in six different ways The labels of the tastes were listed, and the subjects ticked the box they thought was the correct answer Umami was described as ‘‘umami (meaty)” The subjects compared the solution to plain tap water when they tried

to identify the taste In case they did not identify the taste, they were asked to guess

2.4.1.3 Descriptive characterization of two breads (Task 3) The sub-jects were presented with two bread samples in each session All breads were commercial Finnish breads (brand names in parenthe-ses below) and represented different sensory properties At the baseline they were wheat toast (Reilu, Fazer Bakeries) and a

whole-January 2005 BASELINE MEASUREMENT

Sensory instruments Questionnaire to parents

October-December 2004 PILOT TESTING RECRUITMENT

Informed consent (parents)

1 st

WAVE OF SENSORY EDUCATION

April-May 2005

FOLLOW-UP MEASUREMENT

Sensory instruments Questionnaire to parents

January 2006

FOLLOW-UP MEASUREMENT

Sensory instruments

2 nd WAVE OF SENSORY EDUCATION

(for 2/3 of the education group)

May 2006

Sensory instruments Questionnaire to parents

January 2007

Sensory instruments

Fig 1 Flow chart of the experimental procedure of the study.

Table 2 Aqueous aroma solutions (dissolved in tap water) used in the free and aided odor naming.

Free odor naming (Task 1) Aided odor naming (Task 6) Aroma/Ingredient Concentration

(%, w/v)

Aroma/Ingredient Concentration

(%, w/v) Vanilla 1

0.3 Cardamom 1

0.4

Carrot 2

(powder) 0.4 Vinegar 3

33.3 Peppermint 1

0.15 Manufacturers: (1) Quest International, The Netherlands; (2) Givaudan, Switzer-land; (3) Rajamäki, Finland.

Table 3 Mean ratings (SD) of pleasantness and intensity of the aroma solutions in the free odor naming at the baseline (Task 1).

Aroma/ingredient Pleasantness (scale 1–7) Intensity (scale 1–7)

meal rye bread (Real, Fazer Bakeries Oululainen); in the first

fol-low-up regular rye bread (Ruispuikula, Fazer Bakeries) and a sweet

loaf (Setsuuri, Fazer Bakeries); in the second follow-up dark loaf

(Maalahden limppu, Malax Limpan Ltd.) and grainy wheat toast

(Jyväinen IsoPaahto, Vaasan and Vaasan Oy); in the third

follow-up two premium breads, garlicky cheese ciabatta (Artesaani,

Prim-ula Oy) and grainy rye bread (Artesaani, PrimPrim-ula Oy); and in the

last follow-up measurement the subjects described the same

breads that were presented in the baseline measurement The

sub-jects described separately the appearance, smell, taste and texture/

mouthfeel of both samples They were told to avoid words relating

to preference They rinsed their mouths with tap water between

the samples

2.4.1.4 Ratings of the extent to which subjects paid attention to

sensory properties of food (Task 4) In this task, the subjects rated

the extent to which they paid attention to sensory properties

(appearance, odor, taste, texture) of food (scale: 1 = not at all,

2 = slightly, 3 = quite much, 4 = very much)

2.4.1.5 Willingness to taste unfamiliar vs familiar foods (Task 5) The

subjects were presented with 12 (baseline and first follow-up) or

14 (other measurements) pictures of familiar (seven) and

unfamil-iar foods (five/seven) in color The task was to identify which food

was in the picture The subjects then got another booklet in which

the same foods were presented in black and white, with the name

of the food in the upper edge of each picture They were asked to

reply yes/no to the following questions: (1) ‘‘Have you ever seen

this food before?” (2) ‘‘Have you ever tasted this food before?”

and (3) ‘‘Would you like to taste this food?” The first two questions

were used to check whether the foods actually were unfamiliar for

the children Although the results were not analyzed individually,

the distributions strongly suggested that the foods expected to

be unfamiliar to the children actually were unfamiliar

The familiar foods (rye bread, ice cream, blueberry, meat balls,

Edam cheese, carrot, chocolate cookie) were the same for each

fol-low-up point, but the unfamiliar foods were changed At the

base-line and at the first follow-up, the unfamiliar foods were goat

cheese, lychee, sun-dried tomatoes, Naan bread, and frog legs At

the second and third follow-up they were: squid, sheep milk

cheese, carambola, artichoke, couscous, kidney pie, and shiitake

At the last follow-up they were: oyster, Camembert, pitahaya,

avo-cado, sweet potato, reindeer tongue aspic, and endive Even if the

two successive follow-up measurements had the same pictures

of the unfamiliar foods, the familiarity status of each food did

not change as we instructed the children to answer ‘‘yes” only if

they had seen the food for real, not in a picture The food pictures

were kept similar for two successive sessions to make the

compar-ison reliable If the foods had been changed every time, the

unfa-miliarity may have changed because of the foods chosen, and not

for the reasons we were measuring Yet, we had to change some

of the foods a few times during the study, to avoid familiarity

and boredom with the same foods

The task was not performed by the older group in the last fol-low-up session, as that session had a limited space and time frame that required adjustments

2.4.1.6 Aided odor naming (Task 6) The test included five aqueous aroma solutions: cocoa, pineapple, lemon, onion, and peppermint

brown glass vials coded with five letters (H, J, N, L, R) and the presentation order was randomized in five different ways The sub-jects were asked to connect the odor (letter codes in the evaluation form) to the correct label They could choose from 10 labels, of which five were correct The labels (correct ones marked with bold) were: black pepper, banana, cocoa, pineapple, onion, cinna-mon, apple, orange, lecinna-mon, peppermint

2.5 Sensory education program The first wave of sensory education was held between the base-line and the first follow-up measurement in February–April 2005

The lessons followed the principles of the program ‘‘Classes du

the contents and reference materials to suit better to the Finnish environment and the current scientific information on the issues dealt with Each lesson comprised of a short lecture (adapted to

be suitable for children) on the topic, discussion and practical exer-cises The lessons (approximately 1.5 h each) took place at school Two experimenters responsible for the measurements and an assistant gave the lessons each week The contents of the lessons

The second wave of sensory education took place in February–

mea-surement, and consisted of five lessons related to a specific food category at a time (dairy, cereal or meat) Only two school classes out of three from the education group participated in the second education wave The second wave was performed in collaboration with Finnish food industry The personnel of the collaborating food companies, all with an academic degree in food science, gave the lessons Otherwise the practices were similar to the first wave In spite of the effort, no fruit and vegetable supplier nor a fish sup-plier participated in the second wave of education Basically the lessons were similar to the first wave, with a short introduction

to the topic and practical exercises The contents of the lessons

exercises and activation of senses played a major role

2.6 Data analysis The ratings of the two subgroups (one wave or two waves) of the education group did not differ, and thus, the education group was pooled to include all children who received education Re-peated measures of ANOVA (between subjects: treatment educa-tion/control and age group; within-subject: session) were used to examine the effect of age group and sensory education on the per-formance in each of the sensory tasks In the bread description task, only the baseline and final follow-up measurement were in-cluded in the analysis, as the results in between were not compa-rable because different breads were used every time The score of the description task was a sum of descriptive words for appear-ance, smell, taste and texture/mouthfeel (hedonic terms excluded) The effect of education was expected to appear as an interaction of education  session Significant interactions between different ses-sions (within-subject contrasts) are reported, when appropriate The two age groups were analyzed also separately when a trend for age group difference was observed (main effect of age group

or interaction of education  age group  session)

Table 4

Aqueous taste solutions (dissolved in tap water) used in the taste identification test

(Task 2).

Taste identification

Sucrose (sweet) 1

2

Caffeine (bitter) 2

0.04 Monosodium glutamate (umami) 3

0.3 Manufacturers: (1) Dan Sukker, Finland; (2) Fluka Chemicals, Germany; (3) Merck,

Germany

In the free odor naming task, the subjects got one score for each

correctly named odor If they could name a source of an odor

clo-sely associated with the exact odor they got a score 0.5 Thus, the

total score of the odor naming task (0–5) for each subject was the

sum of correctly named and closely associated odors The accepted

nam-ing task was a sum of correctly named odors, thus it could vary

from zero to five (no half scores given)

The score for willingness ratio for trying unfamiliar vs familiar

foods was calculated by dividing the number of affirmative

an-swers given to the question ‘‘Are you willing to try this food?”

for the unfamiliar foods by the corresponding number for the

familiar foods Higher scores reflected greater willingness to taste

unfamiliar foods To correct the uneven ratio of unfamiliar foods

and familiar foods in the baseline and 1st follow-up, the sum of

unfamiliar foods tasted in those two measurements were

multi-plied by 7/5, thus 1.4 Scores lower than 1 reflected a situation in

which the child was willing to taste a greater number of the

famil-iar foods than the unfamilfamil-iar foods, and scores higher than 1 the

opposite situation If a child answered ‘‘No” to all familiar foods

the denominator is equal to 0, thus the ratio is undefined (infinite)

However, none of the children in the present study answered ‘‘No”

to all familiar foods A score equal to1 meant that a child was

equally willing to taste the unfamiliar and familiar foods For five

unfamiliar and seven familiar foods, the range of scores was 0–

2.3 and for seven unfamiliar and seven familiar foods, 0–2,

respec-tively Subtractions between positive answers to the question

‘‘Have you ever seen this food” for unfamiliar foods in the first

fol-low-up and at the baseline (five foods), and between third and

sec-ond follow-up (seven foods) were calculated for each child and

subsequently, the subtractions of the control group and education

group were compared using univariate ANOVA

To check whether an improvement in one task was related to an

improvement in another task a ‘‘score evolution difference” was

cal-culated for each task and each subject separately The individual

improvement in one task leading to improvement in other task were

reported for the three chemosensory tests, i.e free odor naming,

aided odor naming, and taste identification tasks for the education

group The calculations were done manually The score evolution

differences of the tasks were cross-tabulated and Pearson’s

correla-tions between the score evolution differences of the tasks were

cal-culated, but no significant results, even trends were found and

therefore these results have not been included in the result section

3 Results

3.1 The effect of sensory education on performance

in the two age groups

3.1.1 Free (Task 1) and aided (Task 6) odor naming

In the free odor naming task, children were able to correctly

name an average of one odor out of five only The median and

mode for both age groups were 1 and 1 However, in some cases they gave a name that was closely associated to the exact odor The sensory education improved the free odor naming of both the younger age group, 2nd–4th graders [interaction education  session F(4, 62) = 3.90, p = 0.007] and the older group, 5th–7th

p = 0.034] with the exception of the second follow-up measure-ment, in which the performance got poorer compared with the ear-lier measurement The free odor naming of the control group stayed approximately at the same level during the whole study

In the aided odor naming, approximately three odors out of five were identified The median and mode for the young group were 3 and 3 For the older group, the corresponding scores were 4 and 3

No education effect was found Instead, in the younger age group, the control group performed better than the education group in the last two follow-up measurements [interaction of education  ses-sion between 2nd and 3rd follow-up F(1,65) = 4.66, p = 0.035] In the older age group, the performance of the control group impaired after the third follow-up, while the number of correct responses of the education group stayed at the baseline level after the 1st edu-cation wave, but improved in the second follow-up measurement [interaction of education  session between 2nd and 3rd

follow-up F(1, 66)=3.93, p = 0.052; between 3rd and 4th follow-follow-up

3.1.2 Taste identification (Task 2)

identification task [interaction of education x session F(4, 260) = 2.72, p = 0.030] At first, the performance of the younger age group was improved: the education group identified more tastes after the first education period than at the baseline, while

no difference was seen in the performance of the control group [interaction of education x session between baseline and 1st fol-low-up F(1, 65) = 11.76, p = 0.001] In the following sessions, no differences between the groups in the taste identification task were found The education did not have a significant effect on taste identification performance of the older age group (p = 0.322) The percentage of correctly identified tastes (both age groups

all sessions, the easiest taste to identify was sweet (of all sub-jects, 78% identified), followed by salty (60% correct identifica-tions) and sour (51% correct identificaidentifica-tions) Bitter and umami proved to be the most difficult, with identification percentages

improved the identification of the most difficult taste, umami,

in the younger age group [interaction of education  session F(2, 131) = 3.07, p = 0.05] whose identification rate at the baseline was 8.3% and in the final measurement 30.5% For the older chil-dren in the education group, the corresponding figures were 29.1% and 37.3%, respectively The change in the number of cor-rect identifications was not significant for the older group For bitter taste, the increase in identification percentage was not sig-nificant (p = 0.59)

3.1.3 Descriptive characterization of two breads (Task 3) The number of descriptive words (preference-related words ex-cluded) for breads increased in the younger children of the educa-tion group during the study period, while for the control group the number of words was approximately the same for the whole study period [interaction of education  session between baseline and

In the older children, both the education group and the control group, the number of descriptive words decreased from baseline to the final follow-up measurement [main effect of session F(1, 63) = 22.07, p < 0.001] Overall, the number for descriptive words for

Table 5

Free naming of odors (Task 1): descriptions receiving 0.5 score.

Odor Close association

Strawberry Candy, cough medicine a

, chewing gum, raspberry, lemonade, cherry, fruit, juice, marmalade

Carrot Potato, root vegetable, earth, beetroot, rutabaga, pea, vegetable,

zucchini

Vinegar Wine, salad dressing, alcohol, mustard, pickled cucumber

Cardamom Bun (pulla), mulled wine (glögi), cinnamon, spice, gingerbread,

doughnut, ginger

Vanilla Chocolate, caramel, toffee, honey, apple soda b

, marshmallow, candy, ice cream, pastry, syrup, cake

a In Finland, children’s cough medicine is often strawberry-flavored.

b

Finnish apple soda is flavored with vanilla.

breads was higher in the older children than in the younger

chil-dren [main effect of age group F(1, 130) = 48.77, p < 0.001]

3.1.4 Ratings of the extent to which subjects paid attention to sensory

properties of food (Task 4)

attention to taste and least attention to texture of food in both

age groups The only evolution due to sensory education during

the study period was seen as a slight trend in the younger group

to pay more attention to texture of food compared with the control

group [interaction of education  session F(4, 228) = 1.98,

p = 0.086] In the younger children, the education group rated

themselves overall to pay more attention to appearance [main

ef-fect of education F(1, 58) = 6.02, p = 0.017], odor [F = 6.15,

p = 0.016], and taste [F = 4.81, p = 0.032] (means over all sessions),

although no difference was seen at the baseline [ main effect of

education F(4, 69) = 0.64, p = 0.633] In the older age group, no

dif-ference between the education group and the control group was

3.1.5 Willingness to try unfamiliar vs familiar foods (Task 5)

The willingness to taste unfamiliar foods did not change

signif-icantly in either the young group [interaction of education 

ses-sion F(3, 67) = 0.87, p = 0.46] or in the old group [interaction of

The number of positive answers to the question ‘‘Have you ever

seen this food before” did not change significantly between the

sessions For the five unfamiliar foods at the baseline and in the 1st follow-up, the mean change in the education group was 0.79 The change was mostly due to one food, lychee, which was present

in one of the lessons in the first education wave For the control group the corresponding change was 0.56 (effect of education,

p = 0.24) Mean change in the number of positive answers between 2nd and 3rd follow-up was 0.14 for the education group and 0.28 for the control group (effect of education, p = 0.72)

3.1.6 Evolution of performance in the three tests measuring chemosensory awareness

Of the education group, only 26 children in both age groups im-proved in their performance in the free odor naming and 25 chil-dren in the taste identification during the study In the aided odor naming test, 11 children in the younger group and 12 children

in the older group improved their performance during the study In each group, half of them were girls and half of them were boys

In the education group, four children of the young group im-proved in all three tests (free and aided odor naming and taste identification) The corresponding figure for the older group was two Improvement in both the free odor naming and the aided odor naming tasks, but not in taste identification was seen in three chil-dren of the young group and six chilchil-dren of the old group Four children of the young group and one of the old group improved their performance in both aided odor naming and in taste identifi-cation Finally, improvement in free odor naming and in taste iden-tification was seen in ten children of the young group and 11 children of the old group

4 Discussion The free naming of odors proved to be a difficult task for the

study, adults identified approximately two out of the six odors pre-sented, if no cues were given In the cued situation, the

present study, the identification score was at the baseline approx-imately 1 (one odor out of five identified), thus slightly lower than

sensi-tivity compared with adults, but their odor identification is limited due to limitations in linguistic capabilities and familiarity of odor-ants Although the free odor naming task in the present study was difficult, improvement in the performance was observed in the education group after the sensory education period The

improve-0

1

2

3

4

5

2.-4 graders 5.-7 graders

Control (N=79) Education (N=96)

0 1 2 3 4 5

2.-4 graders 5.-7 graders

Control (N=79) Education (N=96)

Fig 2 (a) Free naming of odors, (b) aided naming of odors: mean number (+SEM) of correctly named (or in free naming task also closely associated) odors for the education group and the control group (2nd–4th and 5th–7th graders separately) in the baseline and in the four follow-up measurements (maximum score 5).

0

1

2

3

4

5

Baseline 1

Baseline 1

Control (N=79) Education (N=96)

Fig 3 Taste identification: Mean number (+SEM) of correct responses of the

education group and the control group (2nd–4th and 5th–7th graders separately) in

the baseline and in the four follow-up measurements (maximum score 5).

ment was most likely due to familiarization with odors during the

association between language development and flavor recall in

preschool-aged children: accurate and consistent labeling of flavor improved recall for a variety of stimuli In the present study, the education included labeling of different types of stimuli which

odor identification does not improve identification of odors that are not in the training set In the present study, the same odorants were used for each session, thus the possible improvement in the ability to name odors not presented before remains open Aided odor naming turned out to be a relatively easy task and

no benefit of sensory education was observed Although the scores did not reach maximum at the baseline, the effect of sensory education was assumingly not strong enough to improve an al-ready good performance Furthermore, lemon odor seemed to be more difficult to identify than the others (data not shown), sug-gesting that the lemon aroma used was not a well representative

of the odor

Taste identification of the younger children improved after the first wave of education period and remained more or less at the achieved level throughout the study period In the older group,

no clear improvement was observed The most difficult taste to

identification of a partially separate group of 8-, 9-, 10- and 11-year-old children (n = 348) Although approximately one-third of

0

20

40

60

80

100

Education (N=96) Control (N=79)

0 20 40 60 80 100

Baseline 1 follow-up Final

follow-up

Baseline 1 follow-up Final

follow-up

2.-4 graders 5.-7 graders

Control (N=79) Education (N=96)

Fig 4 (a) Percentage of correctly identified tastes by subjects in the control group and education group in the baseline measurement, age groups pooled, (b) percentage of correct identifications of umami taste for the education group and the control group (2nd–4th and 5th–7th graders separately) in the baseline, 1st and final follow-up measurement (Means and SEM).

0

2

4

6

8

10

12

14

16

2.-4 graders 5.-7 graders

Mean number of descriptive words

Education (N=96) Control (N=79)

Fig 5 Mean number (+SEM) of sensory descriptions per session

(preference-related words excluded) of the bread samples by the education group and the

control group (2nd–4th and 5th–7th graders separately) in the baseline and in the

final follow-up measurement.

1

2

3

4

Odor Taste

Odor Taste

Fig 6 Mean ratings (+SEM) of attention paid to sensory properties of food by the

education group and the control group (2nd–4th and 5th–7th graders separately),

over all follow-up points.

0 1

0.8 0.6 0.4 0.2

Fig 7 The ratio of willingness to try unfamiliar vs familiar foods by the education group and the control group (2nd–3rd and 5th–6th graders separately) in the baseline and in the three follow-up measurements (the older age group did not perform this task in the final follow-up measurement, and therefore the final follow-up point is excluded) See Data analysis for the calculation of the ratio.

the respondents of the present study were included in the data by

Oerlemans et al., some comparison can still be made In the study

by Oerlemans et al., 82, 66, 52, 27 and 23% of children identified

sweet, salty, sour, bitter, and umami tastes, and age groups

per-formed significantly differently only in the identification of salty

taste (8-year-old did not reach the level of the other age groups)

The overall improvement of the taste identification performance

of the younger education group was mostly due to improved

iden-tification of umami Bitter was also a difficult taste to identify at

the baseline, but the identification performance of it did not

im-prove during the study One reason for the imim-provement of the

identification of umami, but not of bitter might be that umami

was overall a new term for almost all of the children and the

curi-osity towards this new taste may thus have improved the

identifi-cation rate

In the sensory characterization of breads, older children used a

greater number of words than did the younger This is in line

with the consistent finding in product evaluation, as younger

chil-dren (3–7 years old) use fewer attributes or dimensions in

com-paring products and forming preferences than older children

using the same breads – the first and the last – showed that in

the younger education group, the number of descriptive words

in-creased significantly Earlier studies have shown that

verbaliza-tion of sensory experiences is supported by taste lessons in

taste lessons (Classes du gỏt program), children described

choco-late in their own way that was different from that of adults In

the present study, the number of words of the older children of

the education group was, unexpectedly, at its lowest in the last

session and for the control group the number was smaller than

at the baseline This may partly be due to the incipient puberty:

in the final follow-up measurement, the students, especially in

the education group, were restless while performing the

descrip-tion task

Children reported to pay attention to taste of food while eating,

rather than to other sensory modalities Children at ages 7–11 are

categorized to be at the analytical stage of socialization as

requir-ing special attention (e.g taste) of a product rather than

immediately observable perceptual features (e.g appearance)

The latter is typical for perceptual stage (ages 3–7 years) Taste

re-mained as the most important attribute for all subjects The overall

ratings show that the younger group paid more attention to

appearance, odor and taste of food than the control group during

the study, although the groups did not differ in their ratings at

the baseline Hence, education in general seemed to activate the

younger children to pay more attention to these attributes in food

The ratio of willingness to taste unfamiliar to familiar foods was

approximately 0.6 at the baseline for both age groups, which was

slightly higher than the corresponding figure of Canadian children

as in Pliner’s study, children were supposed to actually taste the

foods that they reported to be willing to taste, while in the present

study the willingness to taste was rated based on photographs of

foods In the present study, the willingness to taste unfamiliar

foods did not change significantly, although the mean values

tended to decrease The result suggests that sensory education

aged 8–10 years and found that declarative food neophobia of

the education group decreased significantly and the willingness

to taste novel food seemed to increase compared to the control

group However, the effect was only temporary, disappearing after

10 months of the education period

Looking only at the results of the baseline and the first

follow-up measurement, it seems that willingness to taste unfamiliar foods tended to increase in the older age group after the first edu-cation wave, while the effect was opposite for the younger group

will-ingness to taste novel foods in 7–9-year-old children, while it in-creased willingness to taste novel foods in 10–12-year-old children An age effect may thus exist, and the increase in willing-ness to taste unfamiliar foods may result from a certain develop-mental process However, the procedure may also have played a role: the number of follow-up measurements was rather high and may have caused a learning effect in the control group The sensory experiences provided in the follow-up measurements, in-creased children’s awareness of food odors and flavors, and thus may also have increased their interest in new food experiences The result may have been different, if tasting of the foods rather

willingness ratio as neophobia measurement, children were sup-posed to actually taste the foods that they reported to be willing

to taste, increasing the validity of the measurement

The education effect was not quite stable This is in line with

in-crease of willingness to taste novel foods in children disappearing ten months after the education period In the present study, in the tests measuring chemosensory awareness (odor naming and taste identification), the effect was at its strongest right after the educa-tion period and the performance did not improve, but even im-paired later In the free odor naming task, the performance got worse in the second follow-up measurement, while the perfor-mance was at its highest in the final measurement A similar trend could be observed for the taste identification task in the younger age group, but not for other tasks for either age group The second education wave did not affect the performance in the laboratory tasks, perhaps because the education concentrated on fairly general matters rather than on specific chemosensory performance or skills

In a deeper exploration of the reasons for the rather weak effect

of education we observed that the sensory education affected sig-nificantly only a limited number of the children in the tests mea-suring chemosensory awareness The groups with a greater evolution in their performance were equal in their gender distribu-tion and heterogeneous in terms of the class they belonged Thus,

no clear reason can be found for that these children evolved in their performance more than the others Overall, the education had hardly any effects on the performance and perceptions of the older children, compared to the young ones This could partly be explained by the incipient puberty: as the sensory education was more informal than the school curriculum in general, the older children may have related to measurements carelessly Also, the large number of follow-up measurements with similar tests may have decreased their motivation, especially when no feedback on one’s performance was given during the study period In line with

over two years that learning motivation of school children de-crease over the elementary school years

The present study shows that sensory education has potential in activating children’s chemosensory awareness and improving their attention towards foods and also skills to describe foods The ef-fects may not be dramatically large, but they exist The efef-fects were stronger in the younger children, suggesting that a suitable time to start the sensory education program and getting the most of it could be at the age of eight years or even earlier In addition to the measurable effects, the sensory education appealed both to children and school staff It provided a positive and enjoyable way of highlighting food-related sensory issues in the school, as

2007), and teachers (Huotilainen, 2005) The improved skills and

interest in food and eating is not necessarily a measurable effect,

but such development broadens the perspectives to foods and

eat-ing and provides tools in copeat-ing with food choices At its best,

sen-sory education encourages children to try different foods and pay

attention to food quality, which may lead to more healthy and

bal-anced eating habits

Acknowledgements

The authors thank research technician Kaisu Taskila for her

skillful help in laboratory measurements and lessons, and Dr Anna

Huotilainen for conducting the lessons in the first education wave

The representatives of the Finnish companies Valio Ltd., Raisio Ltd.,

Fazer Bakeries and Biofincon Ltd., and Mr Olavi Törmä, MSc, from

the meat pilot plant of the Department of Food Technology are

thanked for contributions to second education wave The

anony-mous reviewers are thanked for their great effort that helped us

improve the paper The interest and encouragement of the SAPERE

Huurn-eman, is acknowledged This study was funded by the research

program of Ministry of Agriculture and Forestry, Finnish

Innova-tion Fund (Sitra) and by Emil Aaltonen FoundaInnova-tion, Finland

Appendix A Appendix

The first wave of the sensory education program

exercises)

-SIGHT: bananas at different ripening states

-SMELL: onion and garlic, what does their smell hint of their other properties?

-HEARING: peeling of potatoes, grating

of carrots, biting a crispbread, peeling a banana (identification blind-folded) -TASTE: dried fruits differing in flavor and color, choosing the favorites and discussion whether the flavor was as expected

-TOUCH: mouthfeel of carrot and crispbread, comparison of how they feel

in hands

-addition of sugar to a sour black currant juice: what happens?

-foods with different salt content: do you taste the difference?

-connecting food with taste (pictures of different foods and taste names)

different aromas (cardamom, carrot, vinegar, pineapple, lemon)

-demonstration of retronasal odor (sip of vanilla aroma solution nose pinched and unpinched)

-comparison of the smells of orange peels, juice and marmalade (intensity, pleasantness)

-drawing task: fruits that smell good -homework: which spices are used at home and how is their smell

Interactions of taste and smell (flavor)

-discussing of foods that go well together

-balancing flavor: tasting plain lemon and discussing the flavor and after that, adding sugar on the lemon and tasting again -off-flavors: fruit salad that has been contaminated with onion flavor -discussion of different off-flavors and their reasons

shape, size -pictures of gourmet dinner, fast food, everyday food: how do they differ? -juices with inappropriate colors (for example red orange juice): discussion -coca cola and diet pepsi: similar appearance, different flavor -green and red salsa, why do they look different?

-homework: description of school lunch Sense of touch and

texture of food

-samples with different texture in opaque bags, description and identification based on touching them with hands

-fruits and vegetables (apple, pineapple, potato), touching and describing the texture, cutting them with knives and evaluating the hardness

-temperature, cold and hot water in a bottle: comparison

-dairy products (yogurt, sour milk and

‘‘viili”) in transparent bottles, observing the movements

-mouthfeel of fat: tasting table spread -trigeminal sensations, hot and cold (chili and peppermint):discussion Traditional Finnish

foods

-tasting traditional Finnish food products like sal ammoniac (‘‘salmiakki”), Finnish Easter pudding (‘‘mämmi”) and oven-baked cheese (‘‘leipäjuusto”)

-where do milk and meat come from? -seasonal foods in Finland: discussing food traditions from January to December Geography of foods

(ethnic foods)

-pictures of ethnic foods, discussion -sensory description of ethnic fruits: lychee, avocado, pitahaya, rambutan, cape gooseberry

-description of appearance, smell and touch feel of herbs

-learning and description of the smell of ethnic spices

-red and green chili sauce

lessons -practical exercises on using one’s senses

in eating

and food: preparing of the food, menus, set out of food, ordering of food, setting for dinner

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consumption of a new food enhances acceptance of similar foods Appetite,

30, 283–295.

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identification: Perceptual and semantic dimensions Chemical Senses, 23,

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Appendix B Appendix

The second wave of the sensory education program

Cereal products (porridge)

(Raisio Ltd)

-tasting and description of porridges made from oat, barley, wheat or rye -effect of temperature on sensory properties of porridge: demonstration -preparation and tasting of cereal-based snacks: fruit smoothie and fresh strawberry porridge

Yogurt and aromas (Valio Ltd

and Biofincon Ltd)

-adding strawberry jam to yogurt: what happens to sweetness, sourness, thickness and flavor intensity?

-tasting salty yogurt and then dipping bread to it: which option do you like more? -acting as a product developer: flavoring of yogurts with different jams (apricot, licorice, banana, tutti-frutti, chocolate, toffee, citrus); letting others to taste and comment Cereal products (rye bread)

(Fazer Bakeries Ltd)

-visit to a large Finnish bakery -tasting of rye bread snacks -creation of descriptive words or slogans related to rye -making sandwiches of rye bread

- getting acquainted with large-scale bread manufacturing (from dough to packages)

-description of four cheese types: Emmenthal, Edam, Brie, blue cheese using cheese flavor wheel

-how fat content affects to sensory properties of cheese (edam) -feta cheese made from cow’s or goat’s milk: how does the milk quality affect their sensory properties?

Meat products (meat pilot

plant of the

Department of Food

Technology)

-getting acquainted with manufacturing of frankfurter in a pilot plant -sensory description of two different types of meat products, salami and frankfurter